[llvm-dev] RFC: Killing undef and spreading poison

[Krzysztof Parzyszek via llvm-dev]

On 10/18/2016 2:25 PM, Nuno Lopes via llvm-dev wrote:
> Right, a load touching a single uninitialized bit results in poison.
> The trick is that on the first bitfield write, all the remaining
> untouched fields become initialized (with an arbitrary value, though).
> Essentially we are making the adjacent bitfields undef.

So "undef" still exists, except now it's obtainable via "freeze(poison)"?

-Krzysztof

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